A paper published by Yale University scientists proposes the rising number of adults and children who experience food allergies may be the result of an exaggerated activation of the body’s system that protects you against eating toxic foods.1 They write that as many as 8% of children in the U.S. have a potentially deadly response to what are classified as the major eight food allergens.
These are often referred to as the “Big 8” and include milk, eggs, wheat, soybeans, fish, crustacean shellfish, tree nuts and peanuts.2 According to data from 2010 referenced by the American Academy of Allergy, Asthma and Immunology, a study of 38,480 children under 18 years revealed the rate of food allergies fluctuated from 6% to 8.5%, depending on the age group.3
A later survey ending in 2016 of nearly identical size (38,408 children) found similar results, which identified 7.6% of children with food allergies.4 The data were gathered from parental surveys and not confirmed testing. They found the most reported allergies were peanut, milk and shellfish.
However, the researchers concluded the prevalence may be higher since they excluded approximately 4% of the reports in which the history was not consistent with a food allergy reaction. The U.S. Centers for Disease Control and Prevention reported a rising rate of food allergies in children from data gathered from 1997 to 2011.5
They found that over a 14-year period the rate of food allergies increased from 3.4% to 5.1%. According to the most recent data from 2016, that rate may have jumped again to 7.6%,6 which means the rate has more than doubled in 19 years. Yale immunobiologists propose this trajectory may be the result of an increasing amount of unnatural substances or environmental chemicals.7
Your Body Has a Food Quality Control System
The rising number of children and adults experiencing food allergies has raised concerns with physicians and researchers. In the paper from Yale University published in the journal Cell, researchers discussed the multiple sensory mechanisms your body uses to monitor what is consumed.8
These systems include smell, taste and chemosensory processes established in the gut and impacted by your gut microbiome. In this paper, the scientists argue that the body has a food quality control system in which an allergic response plays a role. The identification and response against food antigens can result in a lethal food allergy.
One prevailing theory for the rise in food allergies has been a “too clean” environment — called the hygiene hypothesis — where children and adults are no longer exposed to natural pathogens in the environment, triggering the immune system to become hypersensitive.9
Writing in Clinical & Experimental Immunology, scientists expanded the explanation to include the presence of processed foods, dishwashing detergent and other environmental chemicals, as well as a “too clean” environment with the absence of natural microbial exposure.
They argue these all play a role in disrupting the internal food quality control system, designed to help protect your body from noxious chemicals and harmful substances. The group believes this theory may lay the groundwork for future research, treatment or prevention. In a press release from Yale University, one of the authors suggested:10
“We can’t devise ways to prevent or treat food allergies until we fully understand the underlying biology. You can’t be a good car mechanic if you don’t know how a normal car works.
One factor is increased use of hygiene products and overuse of antibiotics and, secondly, a change in diet and the increased consumption of processed food with reduced exposure to naturally grown food and changed composition of the gut microbiome.
Finally, the introduction of food preservatives and environmental chemicals such as dishwashing detergents introduced novel elements for immune systems to monitor.”
When your body detects toxins have been consumed, it also activates the parasympathetic nervous system, intended to help neutralize the health threat.11 This response can trigger food allergies and a lack of natural threats can make the system hypersensitive.
The team believes the collective changes to the food supply and environment have effectively made the immune system respond to food proteins in the same way they would to protect against toxins.
More Potential Reasons for Rising Number of Food Allergies
The furor generated by soaring prices for an EpiPen, a life-saving treatment for the potentially lethal anaphylactic allergic reaction, has made it evident there is a lot of money at stake in the medical treatment of allergies.
As veterinarian Dr. Karen Becker recently covered in one of her Healthy Pets articles, this is another way pets are good for your health. Exposure to dogs and cats can influence the developing immune system of children. Two studies were presented at the American College of Allergy, Asthma & Immunology in 2017 demonstrating children born in homes with a dog had a lower risk of allergic eczema and asthma,12 supporting earlier research.13
The exposure to diverse bacteria and other microbes from dogs has led to them being called “the new probiotic.”14 Dieter Steklis, a professor of psychology and anthropology at the University of Arizona, has studied the physical and microbiome relationship in humans and pets. He spoke with a journalist from the Tucson Sentinel, saying:15
“It’s always surprised me how many diseases and disorders are linked to inflammatory processes that link back to your immune system. If having a dog actually tames your immune system, which is what it seems to do, then elderly who have a dog may have a lower chance of depressive illnesses.”
Other theories that have been proposed for rising food allergies include overuse of medications used to reduce stomach acid, as these can alter your gastrointestinal microbiome.16
Research from King's College London also proposed that when parents avoid introducing young children to foods known to produce an allergy there was an increased potential the child would have a reaction later.17 The study selected children who had a known allergic reaction to eggs or had eczema to evaluate if avoiding an allergen would increase or decrease a food allergy.
The data showed when parents avoided feeding their children peanuts, 13.7% developed an allergy by the time they were 5 years as compared to 1.9% who were introduced to peanuts earlier. Researchers are also questioning if food allergy rates are rising because we spend more time indoors, thus contributing to the fact that vitamin D levels in nearly 40% (39.92%) of the general population are suboptimal.18
Research analyzing EpiPen use in the U.S. found a strong north-south gradient, where more were used in the northern states, suggesting there were “important etiological clues (vitamin D status)” that merit further investigation.19
Similar data were found in Australia two years later when it was revealed EpiPen use and anaphylaxis admissions were more common in areas receiving less sunshine, providing “additional support for a possible role of vitamin D in the pathogenesis of anaphylaxis.”20
Is It a Food Allergy or an Intolerance?
There is a difference between a food sensitivity or reaction and a food allergy. A true food allergy is mediated by the immune system and triggered by a reaction to proteins found in a specific food or drink. Food sensitivities, also called food intolerance, is usually an unpleasant gastrointestinal reaction to something you've consumed but is not mediated by your immune system.21
For example, a true milk allergy is different from lactose intolerance.22 The first triggers an immune response and the second triggers gastrointestinal symptoms from an inability to digest milk proteins. Type 1 food allergies involve immunoglobulin-E (IgE), which is an antibody found in the blood and mast cells in all body tissues.
After you've eaten the food the first time, cells produce IgE for the food protein that triggered the reaction, called an allergen. IgE is released and attaches to the surface of mast cells. This sets the stage for the next time you eat the food that contains the specific allergen. The protein interacts with the IgE on the mast cells and triggers a release of histamine.
IgE reactions sometimes start with itchiness in your mouth, followed by vomiting, diarrhea and stomach pain. Some protein allergens can cross immediately into your bloodstream and trigger a bodywide reaction including dizziness or feeling faint, repetitive coughing, tight, hoarse throat and a weak pulse.23 It can also activate an anaphylactic reaction resulting in a drop in blood pressure, hives and wheezing.
A Type 1 food allergy can take anywhere from a few minutes to a couple of hours to develop. A second type of food allergy, Type 3, is mediated by immunoglobulin-G (IgG). This is a delayed food allergy that happens four to 28 hours after exposure.24
Adult-Onset Food Allergies Are Not Uncommon
Although most food allergies develop in childhood, it is not unheard of for adults to develop a food allergy. Data from a cross-sectional survey of adults living in the U.S. suggest at least 10.8% of adults are allergic to food. Information was gathered from October 2015 to September 2016.25
There were 40,443 adults who completed the survey and while 19% reported some type of food allergy, only 10.8% reported symptoms concurrent with an IgE reaction. The study was published in the Journal of the American Medical Association in a collaboration between Stanford food allergy expert Dr. Kari Nadeau and scientists at Northwestern University.26
The researchers believe this contradicts a long-held belief that most allergies develop in childhood. Past data had estimated 9% of adults had true food allergic responses. In the cohort, researchers found 38% of those they determined to have food allergies had experienced a reaction that sent them to the emergency room and 48% reported at least one food allergy was triggered after age 18.
Some food allergies developed as an adult can be severe, such as the reactions that graduate student Amy Barbuto experienced in a Thai restaurant. In an interview with a journalist from Texas Medical Center, Barbuto recounted her first allergic response at the restaurant.27
Before that day she had a food intolerance to gluten, but in 2011 she suffered an anaphylactic reaction when the wrong soy sauce was used in her food. Since then she was hospitalized 25 times from 2011 to 2020 for allergic reactions. She talked about the difficulty of avoiding gluten, saying:28
“It’s a hard one to avoid, even when you work your hardest to avoid it. My allergy is so severe that I could get exposed and not even know it. My food can look gluten-free, look normal … but all it would take is somebody having touched bread and then touched my plate.”
Reduce Your Potential Risk for Food Allergies
As Barbuto’s story demonstrates, food allergies can develop well into adulthood and become potentially lethal. There are steps you can take to lower your potential risk of developing an allergy or experiencing an anaphylactic response.
Your gut microbiome is vital to the health and optimal functioning of your immune system, which mediates an allergic response to food. By caring for your gut microbiome, you help protect your health. As I’ve written before in “How Your Gut Health Impacts Your Disease Risk”:
- Fermented foods help repopulate your gut with healthy bacteria
- Antacids change your stomach acid and negatively affect your gut microbiome
- Steer clear of antibiotics, including in your food, unless absolutely necessary, and take a quality probiotic when you must use antibiotics
- Reduce or eliminate processed foods, as they are high in sugar that feed harmful bacteria in your gut
- Optimize your vitamin D levels through sensible sun exposure or supplementation if you live in areas with little sun. There are strategies you can use to achieve your vitamin D goals, as I shared in “The Most Important Paper Dr. Mercola Has Ever Written”